actually... the filter is already a nice cone filter, its just confined in a box, if you were to open that box a bit AND upgrade the exhaust, you would free up some HP, but loose some water fording abilities. as far as exhaust... it has a pretty hefty pipe, the muffler and cat are probably the biggest restrictions.. replacing the muffler won't do much unless you replace the cat, and those are not cheap...
2012 FDII Patriot
Mods: 245/65-17 Falken Rocky Mountain ATS, RRO lift
http://goo.gl/h3lf9 - youtube channel.